This invention relates generally to systems and methods for determining the service life of air filters, and more particularly, for a system and method for calculating the service life of cartridges for air purifying respirators.
Determination of the service life of filter cartridges or filter beds in the filter cartridges of air purifying respirators is a regulatory requirement in the United States. Moreover, many users of air purifying respirators desire to have change out data and/or an estimated service life calculation. Change out data may include, for example, a schedule for when the cartridges in air purifying respirators should be changed out, or replaced, with new cartridges. The estimated service life calculation may include a determination of how long the cartridges in an air purifying respirator should last. Both the change out data and the estimated service life calculation may be based in whole or part on the input of the conditions in which the cartridges and respirators are used.
Known methods and systems used to determine change out data and service life calculations for air purifying respirator cartridges have several shortcomings. For example, known systems and methods do not provide a graphical output of an effluent concentration profile, a breakthrough time or a service life of a filter cartridge. Also, these systems and methods do not provide for dynamic calculation of an effluent concentration profile, a breakthrough time or a service life based on dynamically changing inputs from a user. Moreover, to the extent these systems and methods do determine a breakthrough time or service life, the mathematical models upon which the breakthrough time or service life is based do not accurately determine the breakthrough time or service life for many contaminants, including many contaminants having relatively low molecular weights and/or low boiling points.
Thus, a need exists for a system and method for determining change out data and service life calculations for air purifying respirator cartridges that provide a graphical output of effluent concentration profiles, allow for dynamic calculations of service life calculations and are based on more accurate models